1. Field of the Invention
The present invention relates to radiation detection or inspection systems and, more particularly, to radiation detector arrays and corresponding collimators for use in said inspection systems.
2. Description of Related Art
Many radiation inspection systems employ CZT, CdTe, Ge or other types of radiation-sensitive semiconductor detectors assembled into linear arrays for the purpose of converting radiation impinging on said detectors into corresponding electrical signals.
There are known inspection systems having radiation detectors where all of the pixels (or radiation detection elements) thereof are arranged in single or multiple rows and all detectors are arranged in a single line (a linear array) to cover a scanning area cross section where a radiation pattern is defined by radiation passing through a single slot collimator disposed in the path of the radiation for improving image quality and resolution.
More specifically, heretofore, radiation detectors of inspection systems were arranged into linear arrays with a single slot collimator above them. In order to keep pixel pitch constant and to allow gaps in between the detectors, the edge pixels of each detector were made undersized and a guard band was only provided along the two sides of the detector, leaving exposed unguarded edge pixels on either end of the detector. Due to differences in pixel width, electric field geometry inside the detector and pixel surrounding conditions, edge pixels exhibited different performance versus internal pixels. Edge pixels have also been observed to be prone to instability and performance degradation due to changes to the detector sides over time and increase leakage current.
Heretofore, traditional radiation detectors were placed very close to each other, e.g., end-to-end, to maintain pixel pitch across the array. This arrangement, however, often presents the technical challenge and risk of damaging adjacent detectors during installation or due to thermal expansion.
It would, therefore, be desirable to provide a radiation inspection system that has a new arrangement of radiation detectors that avoids the above problems and others, as well as a collimator for use with such new detector array. Still other advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.